Jiang Yonggang, He Qipei, Cai Jun, Shen Dawei, Hu Xiaohe, Zhang Deyuan
School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China.
Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China.
ACS Appl Mater Interfaces. 2020 Dec 30;12(52):58317-58325. doi: 10.1021/acsami.0c19484. Epub 2020 Dec 15.
Carbon-based piezoresistive nanomaterials are widely used for the fabrication of flexible sensors. Although our previous work demonstrated that an electrical breakdown (EBD) process can endow a graphene/polyimide (G/PI) composite with piezoresistivity, the formation of EBD-induced electrical traces with high consistency in bulk nanocomposites remains a technical challenge. With the aim of developing highly sensitive flexible strain sensors using a batch fabrication process, we introduce herein a microscale EBD (μEBD) method to form localized piezoresistors with diverse shapes in a G/PI thin film. The results of scanning electron microscopy, Raman spectroscopy, and electromechanical tests indicate that high piezoresistivity is derived from the high porosity of the carbonized conductive traces generated by the μEBD process. The gauge factor of the μEBD-treated G/PI strain sensor is over 20 times greater than that of the as-prepared G/PI film, and the sensitivities of the strain sensors can be tuned by varying the applied current in the μEBD process. We also demonstrate the potential applications of μEBD-treated G/PI strain sensors in the fields of finger gesture detection, sound pressure measurement, and airflow sensing.
碳基压阻纳米材料被广泛用于制造柔性传感器。尽管我们之前的工作表明，电击穿（EBD）过程可赋予石墨烯/聚酰亚胺（G/PI）复合材料压阻特性，但在块状纳米复合材料中形成具有高度一致性的EBD诱导电迹线仍然是一项技术挑战。为了使用批量制造工艺开发高灵敏度柔性应变传感器，我们在此引入一种微尺度电击穿（μEBD）方法，以在G/PI薄膜中形成各种形状的局部压阻器。扫描电子显微镜、拉曼光谱和机电测试结果表明，高压阻率源自μEBD过程产生的碳化导电迹线的高孔隙率。经μEBD处理的G/PI应变传感器的应变系数比制备好的G/PI薄膜大20倍以上，并且可以通过改变μEBD过程中的施加电流来调节应变传感器的灵敏度。我们还展示了经μEBD处理的G/PI应变传感器在手指手势检测、声压测量和气流传感领域的潜在应用。
